“Get A Grip!” Microphone effects controller

[Matthew Sanford]

I got a few pressure/force sensors for presents ( 2Pcs Thin Film Pressure Sensor High Precise Force Sensitive Resistor Force Sensor Pressure Sensor Resistance Type Thin Film Pressure Sensor Force Sensing Resistor https://a.co/d/gX790Ha)

I'd thought forever ago a mic effect chain control with flywheels to vary the level, but with this it's easy. Just tap the hot and ground (xlr), run hot to the sensor then it and ground to a 1/4" Jack to run a cable to a pedal chain. Oh, and tape the sensor where your forefinger goes...at least that was my prototype (with a breadboard and lots of tape!)

Now all the last words can echo!!!

Truly the sensor is very sensitive (thinking foam on top to lessen the pressure?). I had thought to do a TRRS to send both sides, signal, and ground to a box to control the flow of signal, or better yet diy effects with taps all over and four sensors (not just volume, eh?). I guess that'd take more wires, maybe a VGA connector or D15 like an Atari 400.

[stonerbox]

Reminds me of Reznor's echo controller.
https://youtu.be/sSVOgQKiYQ4?t=531

[Matthew Sanford]

Right? Like that...wonder how he's working it.

I want it like as Gandalf gets frustrated with Bilbo and it takes on deep reverb slowly (in my mind...that's how it went right?) before saying "I'm not trying to rob you...I'm only trying to help you"

I'm having sensitivity issues though, I cut open a cotton ball, ended up covering it in electrical tape (it was shorting the sensor) and put it around the sensor. It reduced the sensitivity a little, but I'm wondering if putting, say, a 2M resistor in parallel would lessen the rate of change of the sensor? Right now pin 2 (hot)is going through that to the pedal chain...oh, and connecting the xlr ground to the 1/4 cuts the whole signal.

Still, any ideas to make it reduce resistance slower? Maybe 5 extra huge resistors in parallel?

[Matthew Sanford]

Ok...voltage divider with a 1M (22k after doing calculations) to ground. It's range is 2.2k (measured) to 20M+ (unable to measure) and when triggered <200k (per mAmazon). I'm thinking that should start it really low then grow... dummy check, I should put it to the 1/4 ground, not the mic?

[Matthew Sanford]

So, I need a little help. First, I drew out the schematic and realized what I thought was xlr ground was xlr cold...so I fixed that and yes, grounds should connect.




It works! But...it sometimes is noisy, like plugging your guitar in to effects when the amp is already on. I did modify arduino jumpers and am only pressing them into the xlr with the sensor plugged in to the female ends, so nothing is very solid yet, and using a breadboard taped to the cord to get it together.

My thought is it's connecting at the sensor gets disturbed and creates noise, but what else could cause it? Also, maybe I need a cap between the xlr and the sensor to block phantom power? Didn't seem to make a difference on the board, but that's a bit down the line...would the dc affect the force resistor?

[Matthew Sanford]

For posterity: I added two caps; C1 220uf before the FSR (in series), and C2 27nf after FSR to ground. High/low at opposite points kill the signal either way. Voltage divider just added noise...but then now I'm thinking in series to ground with C2 might help? Guess one more breadboard before I cut the cable and wire one up...

Oh, and I taped the sensor to a piece of plastic to keep it flat, that cleaned up a lot.

Should the xlr connectors be as one or with a short cable between? Just don't want a real long looking mic...

Schem for posterity

[Matthew Sanford]

Ok, it's finished! Yes resistor to ground through 27n cap takes care of noise divider noise. Also the sensor's trigger point let's off a pop, so I used a bit of sports tape with the same to tape it down just past trigger, likely ~200k (datasheet, not measured)...popping made me feel like I was back in the fire swamp!

Without further ado, the schem



And the video that I wasn't paying enough attention to while doing it, but it's studio one w/spectrum meter on the effected signal

https://youtu.be/gCikzaotvEI

[Matthew Sanford]

Sorry to bring back this old thing, but I soldered together a working prototype! I ditched the proper FSR and 220uf cap, made FSRs from 1/4" x 1/2" conductive foam (not anti-static!) & copper tape and they work better! So on the scheme above, the hot to that 2 contact screw connector and the other to 1/4" jack. The resistor/cap is in the 1/4 jack. A 2.0 version will be cv controls, but that doesn't need to tap the xlr.

Ok, pictures!


Blue tape over sensor and wire, plugs in the blue 2 contact thing, lower down 1/4"F and XLR M.


The sensor, I didn't fully shrink the heat shrink on it, will figure something better cause one slightly bleeds vocals through as it is being squeezed a bit.



This just to zoom in a bit

[garcho]

Nice work

[Matthew Sanford]

Thanks! I'm excited to try it out next weekend for a madness birthday jam, plan to record and film so if I get it together may post it here. Now I'm thinking how else to use FSRs, placed on a synth for stuff, or in the guitar out jack (after a series cap) to ground for a hpf on the guitar face...all the options!